Organic electroluminescent display device

ABSTRACT

An organic electroluminescent display device is disclosed which includes: a lower substrate including a first substrate defined into red, green and blue sub-pixel regions, first and second switching elements formed in the red and green sub-pixel regions, first and second anodes each connected to the first and second switching elements, and a first organic light emission layer entirely formed on the first substrate provided with the first and second anodes; and an upper substrate including a second substrate, red and green color filter layers formed on the second substrate corresponding to the red and green sub-pixel regions, a third switching element formed on the second substrate corresponding to the blue sub-pixel region, a third anode connected to the third switching element, and a second organic light emission layer entirely formed on the second substrate provided with the red and green color filter layers and the third anode.

This application is a divisional of U.S. patent application Ser. No.13/660,417, filed Oct. 25, 2012, and also claims the priority of KoreanPatent Application Nos. 10-2011-0110806, 10-2011-0110807, and10-2011-0110808, filed on Oct. 27, 2011, all of which are herebyincorporated by reference in their entireties.

BACKGROUND

1. Field of the Disclosure

The present application relates to an organic electroluminescent displaydevice.

2. Description of the Related Art

Recently, flat display device have been actively researched in order toenhance display quality and enlarge the screen size. Among the flatdisplay device, organic electroluminescent display devices areself-illuminating display devices. In order to display images, theorganic electroluminescent display devices display emit light by formingexcitons images through the recombination of carriers such as anelectron and an electric hole.

The organic electroluminescent display device can be used as a pixel ofa graphic display system, an image display device of a televisionsystem, a surface light source, or others, because of having featuressuch as a wide viewing angle, high speed response, a high contrast ratioand so on. Moreover, the organic electroluminescent display device withlight weight, thin thickness and superior color vision is considered tobe a next generation display device.

Also, the organic electroluminescent display device is classified into apassive matrix type and an active matrix type. An organicelectroluminescent display device of the active matrix type includesthin film transistors, but an organic electroluminescent display deviceof the passive matrix type does not include any thin film transistor.

Such an organic electroluminescent display device includes organic lightemission elements each formed in pixel regions. Each of the lightemission elements includes an organic light emission layer which isinterposed between an anode and a cathode and formed from an organiclight emission material.

The organic light emission layer of the organic light emission elementincludes a plurality of functional layers, such as a hole injectionlayer, a hole transport layer, a light emission layer, an electrontransport layer, an electron injection layer or others. The combinationor arrangement of functional layers can enhance the light emissionefficiency of the organic light emission element.

The above-mentioned organic light emission layer is ordinarily formed inthe pixel region of the organic electroluminescent display device usinga vacuum deposition process which allows an organic light emissionmaterial to be deposited on a substrate.

In the vacuum deposition process, an organic light emission materialused to form the organic light emission layer is placed into adeposition source with an outlet. The deposition source is heated withina vacuum chamber and enables the organic light emission material to bevaporized and discharged through the outlet. As such, the vaporizedorganic light emission material can be discharged from the depositionsource and deposited on the substrate.

If the organic electroluminescent display device including a pluralityof organic light emission layers with desired patterns is fabricated,the deposition process is performed using a shadow mask having aplurality of openings. More specifically, the shadow mask is positionedclosely to the substrate. Then, the vaporized organic light emissionmaterial is deposited on the substrate through the shadow mask.Therefore, the organic light emission layer having a plurality ofdesired patterns which are separated from one another can be formed onthe substrate.

FIG. 1 is a view illustrating an ordinary process of forming an organiclight emission layer of the organic electroluminescent display device.As shown in FIG. 1, the organic electroluminescent display deviceincludes red, green and blue organic light emission layers R, G and Bwhich are formed in an active area. The red, green and blue organiclight emission layers are formed on the substrate 10 by heating a boatinto which the organic light emission material is filled.

More specifically, when a substrate 10 in which organic light emissionlayers will be formed is loaded into a chamber, a shadow mask 30 placedon a mask frame 15 is aligned with the substrate 10. Then, boats 20holding red, green and blue organic light emission materials aresequentially heated. As such, the red, green and blue organic lightemission layers R, G and B are sequentially formed on the substrate 10.As the boats 20 are sequentially heated, shadow masks each opposite tored, green and blue sub-pixels are replaced alternately with one anotherin order to form the red, green and blue organic light emission layersR, G and B in red, green and blue sub-pixel regions.

However, when the shadow masks 30 are used in the formation of theorganic light emission layers, the organic light emission materialscannot be uniformly deposited on the substrate 10. To address thismatter, the distance between the shadow mask 30 and the boat 20 canincrease. In this case, the organic light emission layer can be pollutedby other materials and moved apart from a desired formation position dueto the contact of the shadow mask 30 with the substrate 10.

Moreover, a large sized organic electroluminescent display device forcesthe size of the shadow mask to become larger. The enlarged shadow maskcan be bent with its central portion in the center. Due to this, it isdifficult to accurately form the organic light emission layer.

BRIEF SUMMARY

Accordingly, embodiments of the present application are directed to anorganic electroluminescent display device that substantially obviatesone or more of problems due to the limitations and disadvantages of therelated art, as well as a method of fabricating the same.

The embodiments are to provide an organic electroluminescent displaydevice and a fabricating method thereof that are adapted to realizelarge size and high definition by distributing organic light emissionlayers to two substrates.

Also, the embodiments are to provide an organic electroluminescentdisplay device and a fabricating method thereof that are adapted toprevent the deterioration of productivity ratio due to the generation ofdifferent materials by entirely coating an organic light emission layeron a substrate without using any shadow mask.

Moreover, the embodiments are to provide an organic electroluminescentdisplay device and a fabricating method thereof that are adapted torealize large size and high definition by distributing first and secondorganic light emission layers to red and green sub-pixel regions andblue sub-pixel region and outputting red light, green light and bluelight using only red and blue color filter layers.

Furthermore, the embodiments are to provide an organicelectroluminescent display device and a fabricating method thereof thatare adapted to realize large size and high definition by forming anorganic light emission layer in red and green sub-pixel regions usingone of an ink-jet printing method and a nozzle-jet printing method.

Additional features and advantages of the embodiments will be set forthin the description which follows, and in part will be apparent from thedescription, or may be learned by practice of the embodiments. Theadvantages of the embodiments will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

According to a first general aspect of the present embodiment, anorganic electroluminescent display device includes: a lower substrateincluding a first substrate defined into red, green and blue sub-pixelregions, first and second switching elements formed in the red and greensub-pixel regions, first and second anodes each connected to the firstand second switching elements, and a first organic light emission layerentirely formed on the first substrate provided with the first andsecond anodes; and an upper substrate including a second substrate, redand green color filter layers formed on the second substratecorresponding to the red and green sub-pixel regions, a third switchingelement formed on the second substrate corresponding to the bluesub-pixel region, a third anode connected to the third switchingelement, and a second organic light emission layer entirely formed onthe second substrate provided with the red and green color filter layersand the third anode.

An organic electroluminescent display device according to a secondgeneral aspect of the present embodiment includes: first through thirdswitching elements formed in red, green and blue sub-pixel regions intowhich a substrate is defined, respectively; a passivation layer entirelyformed on the substrate which is provided with the first through thirdswitching elements; red and green color filter layers formed on thepassivation layer corresponding to the red and green sub-pixel regions;first and third anodes formed in the red, green and blue sub-pixelregions, respectively; an organic light emission layer pattern formed onthe substrate which is provided with the first through third anodes; afirst cathode formed on the organic light emission layer pattern; anorganic light emission layer formed on the substrate which is providedwith the first cathode; and a second cathode formed on the organic lightemission layer.

An organic electroluminescent display device according to a thirdgeneral aspect of the present embodiment includes: first through thirdswitching elements formed in red, green and blue sub-pixel regions intowhich a substrate is defined, respectively; a passivation layer entirelyformed on the substrate which is provided with the first through thirdswitching elements; red and green color filter layers formed on thepassivation layer corresponding to the red and green sub-pixel regions;first and third anodes formed in the red, green and blue sub-pixelregions, respectively; a hole support layer formed on the substratewhich is provided with the first through third anodes; a first organiclight emission layer formed on the hole support layer corresponding tothe red and green sub-pixel regions; a second organic light emissionlayer formed on the substrate which is provided with the first organiclight emission layer; an electron support layer formed on the secondorganic light emission layer; and a cathode formed on the electronsupport layer.

Other systems, methods, features and advantages will be, or will become,apparent to one with skill in the art upon examination of the followingfigures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the present disclosure, and beprotected by the following claims. Nothing in this section should betaken as a limitation on those claims. Further aspects and advantagesare discussed below in conjunction with the embodiments. It is to beunderstood that both the foregoing general description and the followingdetailed description of the present disclosure are exemplary andexplanatory and are intended to provide further explanation of thedisclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the embodiments and are incorporated herein andconstitute a part of this application, illustrate embodiment(s) of thepresent disclosure and together with the description serve to explainthe disclosure. In the drawings:

FIG. 1 is a view illustrating an ordinary process of forming an organiclight emission layer of the organic electroluminescent display device;

FIGS. 2A through 2G are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to afirst embodiment of the present disclosure;

FIGS. 3A through 3G are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to asecond embodiment of the present disclosure;

FIGS. 4A through 4F are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to athird embodiment of the present disclosure;

FIGS. 5A through 5E are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to afourth embodiment of the present disclosure;

FIGS. 6A through 6E are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to afifth embodiment of the present disclosure;

FIGS. 7A through 7E are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to asixth embodiment of the present disclosure;

FIG. 8 is a cross-sectional view illustrating a method of fabricating anorganic electroluminescent display device according to a seventhembodiment of the present disclosure;

FIGS. 9A through 9F are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to aneighth embodiment of the present disclosure; and

FIGS. 10A through 10F are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to aninth embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. These embodiments introduced hereinafter are provided asexamples in order to convey their spirits to the ordinary skilled personin the art. Therefore, these embodiments might be embodied in adifferent shape, so are not limited to these embodiments described here.In the drawings, the size, thickness and so on of a device can beexaggerated for convenience of explanation. Wherever possible, the samereference numbers will be used throughout this disclosure including thedrawings to refer to the same or like parts.

FIGS. 2A through 2G are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to afirst embodiment of the present disclosure.

Referring to FIGS. 2A through 2G, a first substrate 100 is prepared.Although they are not shown in the drawings, a plurality of gate linesand a plurality of data lines crossing each other are formed on thefirst substrate 100 in such a manner as to define a plurality ofsub-pixel regions. Also, thin film transistors TFT are formed in onlyred and green sub-pixel regions among the sub-pixel regions, asswitching elements. In other words, the organic electroluminescentdisplay device of the first embodiment enables the switching elements tobe distributed to both sides of the first substrate 100 and a secondsubstrate 200 which will be described as an upper substrate later. Indetail, the switching elements used for the red and green sub-pixels areformed on the red and green sub-pixel regions of the first substrate100, but the switching elements used for blue sub-pixels are formed onthe second substrate 200.

In the present disclosure, the organic electroluminescent display deviceincluding pixels each configured with the red, green and blue sub-pixelswill be mainly described.

As shown in the drawings, a first switching element T1 and a secondswitching element T2 are formed on the red and green sub-pixel regionsof the first substrate 100, respectively. A passivation layer 101 isformed on the entire surface of the first substrate 100 provided withthe first and second switching elements T1 and T2.

Although the structure of each switching element T1 and T2 is not shownin the drawings, one of a top-gate thin-film transistor and abottom-gate thin-film transistor, which are generally being used in theorganic electroluminescent display devices, can be formed as a switchingelement.

After the above-mentioned passivation layer 101 is formed on the firstsubstrate 100, a contact hole formation process is performed for thepassivation layer 101 and then a first bank pattern 103 used forseparating the sub-pixels from one another is formed on the passivationlayer 101. The contact hole formation process allows drain electrodes ofthe first and second switching elements T1 and T2. The first bankpattern 103 can be prepared by forming an organic film on the entiresurface of the first substrate 100 with the contact holes and performinga photolithography procedure, which includes a masking process, for theorganic film.

Thereafter, first and second anodes 120 a and 120 b are formed in thered and green sub-pixel regions R and G of the first substrate 100. Thefirst and second anodes 120 a and 120 b can be prepared by forming ametal film on the entire surface of the first substrate 10 provided withthe first bank pattern 103 and performing a masking process and an etchprocess for the metal film. The metal film can be formed from one ofmagnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li and alloysthereof.

Alternatively, the first and second anodes 120 a and 120 b can be formedbefore the first bank pattern 103 used to separate the sub-pixels fromone another, after the passivation layer 101 is formed on the firstsubstrate 100 and the contact hole formation process is performed forthe passivation layer 101.

Subsequently, as shown in FIGS. 2B and 2C, an organic light emissionlayer 105 and a first cathode 106 are sequentially formed on the firstsubstrate 100 so that the fabrication of a lower substrate 110 for theorganic electroluminescent display device is completed. The firstcathode 106 can be formed from a transparent conductive material such asindium-tin-oxide ITO, indium-zinc-oxide IZO or aluminum-zinc-oxide AZO.The first organic light emission layer 105 can be formed from an organicmaterial adapted to emit a mixture of red light and green light.

When the lower substrate 110 of the organic electroluminescent displaydevice is completely fabricated as described above, the third switchingelement T3 is formed in the blue sub-pixel region B of the secondsubstrate 200 and an insulation layer 201 is formed on the entiresurface of the second substrate 200 provided with the third switchingelement T3, as shown in FIG. 2D. The third switching element T3 isformed in the same structure as the first and second switching elementsT1 and T2. Also, the third switching element T3 has the same function asthe first and second switching elements T1 and T2.

In other words, the first through third switching elements T1 through T3are formed in the red, green and blue sub-pixel regions R, G and B,respectively, but distributed to the first and second substrates 100 and200. In detail, the first and second switching elements T1 and T2 eachopposite to the red and blue sub-pixels are formed on the firstsubstrate 100 of the lower substrate 110, but the third switchingelement T3 opposite to the blue sub-pixel is formed on the secondsubstrate 200 of the upper substrate 210.

The insulation layer 201 can become a planarization layer. Also, theinsulation layer 201 can be formed in a multilayered structure.

After the third switching element T3 and the insulation layer 201 areformed on the second substrate 200, a second bank pattern 203 definingthe sub-pixel regions is formed on the second substrate 200. The secondbank pattern 203 can be prepared by forming a metal film or an opaqueresin layer on the insulation layer 201 and performing a masking processfor the metal film or the opaque resin layer. The metal film used in theformation of the second bank pattern 203 can be formed a metal materialsuch as chromium Cr.

When the second bank pattern 203 is formed on the second substrate 200as described above, a red color filter layer R and a green color filterlayer G are formed in red and green sub-pixel regions of the exposedinsulation layer 201 opposite to the first and second anodes of thefirst substrate 100, respectively.

Also, a third anode 120 c is formed in a blue sub-pixel region B of theexposed insulation layer 201. The third anode 120 c can be prepared byforming a transparent conductive material film on the second substrate200 provided with the red and green color filter layers R and G andperforming another masking process for the transparent conductivematerial film. In other words, the third anode 120 c can be formed froma transparent conductive material such as indium-tin-oxide ITO,indium-zinc-oxide IZO or aluminum-zinc-oxide AZO, unlike the first andsecond anodes on the first substrate 100.

Alternatively, the red and green color filter layers R and G and thethird anode 120 c can be formed on the insulation layer 201 before theformation of the second bank pattern 203.

After the red and green color filter layers R and G and the third anode120 c are formed on the second substrate 200, a second organic lightemission layer 205 is formed on the entire surface of the secondsubstrate 200, as shown in FIG. 2E. The second organic light emissionlayer 205 is formed from an organic material adapted to emit blue light,unlike the first organic light emission layer 105.

Thereafter, a second cathode 206 is formed on the second organic lightemission layer 205 of the second substrate 200 so that the fabricationof an upper substrate 210 of the organic electroluminescent displaydevice is completed. The second cathode 206 is formed on a part of thesecond organic light emission layer 205 corresponding to the bluesub-pixel region in which the red and green color filter layers R and Gare not formed.

In order to form the second cathode 206, an electrode film including alight-to-heat conversion layer 222, a buffer layer 221 and a metallayer, which are stacked on a base substrate 223, is attached to thesecond organic light emission layer 205, and laser light is irradiated apart of the electrode film corresponding to the region in which thesecond cathode 206 will be formed. When laser light is irradiated on apart of the electrode film, the light-to-heat conversion layer 222generates high-temperature heat and forces a part of the metal layer onthe buffer layer 221 to be attached to the second organic light emissionlayer 205. In accordance therewith, the second cathode 206 is formed onthe second organic light emission layer corresponding to the bluesub-pixel region. Although it is shown in the drawing, a referencenumber “207” not cited in the above description indicates a sacrificiallayer. The sacrificial layer 207 corresponds to the residual metal layerwhich remains on the electrode film after the formation of the secondcathode 206.

The second cathode 206 can be formed from an opaque metal with a highreflectance, unlike the first cathode 106. This results in that bluelight generated in the second organic light emission layer 205 isreflected by the second cathode 206 and is output toward the rearsurface of the second substrate 200 through third anode 120 c.

When the fabrication of the upper substrate 210 including the red andgreen color filter layers R and G and the third switching element T3 inthe blue sub-pixel region is completed, as shown in FIG. 2G, the uppersubstrate 210 and the lower substrate 110 are combined with each otherby means of an adhesive layer 250. As such, a completed organicelectroluminescent display device is produced.

The organic electroluminescent display device according to a firstembodiment of the present disclosure allows not only the red and greencolor filter layers R and G to be formed in the red and green sub-pixelregions, respectively, but also the second organic light emission layer205 emitting blue light to be formed in the blue sub-pixel region. Inother words, a blue color filter layer is not formed in the bluesub-pixel region.

Also, the first and second organic light emission layers 105 and 205 canbe formed on the first and second substrates 100 and 200 through thecoating process or the deposition process and without using any shadowmask. As such, the organic electroluminescent display device of thefirst embodiment can prevent the previous problems which had beengenerated in that of the related art due to the use of the shadow mask.

In the red sub-pixel region, the mixture of red light and green lightgenerated in the first organic light emission layer 105 is re-mixed withblue light generated in the second organic light emission layer 205. Assuch, the re-mixed light can pass through the red color filter layer R.Therefore, red light can be output from the red sub-pixel. Similarly tothis, green light can be output from the green sub-pixel. Meanwhile, inthe blue sub-pixel region, only blue light generated in the secondorganic light emission layer 205 can be output through the third anode120 c. In this manner, the organic electroluminescent display device ofthe first embodiment can enable red, green and blue lights to be outputfrom the red, green and blue sub-pixel, thereby displaying a colorimage.

The organic electroluminescent display device and the fabricating methodthereof according to the present embodiment allow the organic lightemission layer to be distributed to the two substrates and formedthrough only the coating process or the deposition process. As such, alarge-sized screen and a high-definition image can be provided.

Moreover, the organic electroluminescent display device and thefabricating method thereof according to the present embodiment enablethe organic light emission layer to be formed without using any shadowmask. In accordance therewith, the deterioration of productivity ratiodue to the generation of different materials can be prevented.

FIGS. 3A through 3G are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to asecond embodiment of the present disclosure.

The description of the second embodiment will be focused on componentsof the second embodiment which are distinguished from those of the firstembodiment. Also, it will be easily understood to an ordinary personexplanation regarding the other components of the second embodiment,which will be not explained in detail, upon the above-mentioneddescription of the first embodiment.

As shown in FIGS. 3A through 3G, a first switching element T1 and asecond switching element T2 are formed on red and green sub-pixelregions of the first substrate 100, respectively. A passivation layer101 is formed on the entire surface of the first substrate 100 providedwith the first and second switching elements T1 and T2.

Subsequently, a first bank pattern 103 is formed on the passivationlayer 101. Also, first and second anodes 120 a and 120 b are formed inthe red and green sub-pixel regions of the passivation layer 101.

Afterward, as shown in FIGS. 3B and 3C, an organic light emission layer105 and a first cathode 106 are sequentially formed on the firstsubstrate 100 so that the fabrication of a lower substrate 110 for theorganic electroluminescent display device is completed. The firstcathode 106 can be formed from a transparent conductive material such asindium-tin-oxide ITO, indium-zinc-oxide IZO or aluminum-zinc-oxide AZO.The first organic light emission layer 105 can be formed from an organicmaterial adapted to emit a mixture of red light and green light.

When the lower substrate 110 of the organic electroluminescent displaydevice is completely fabricated as described above, a third switchingelement T, an insulation layer 201, a second bank pattern defining aplurality of sub-pixel regions, red and green color filter layers R andG, and a third anode 120 c are sequentially formed on a second substrate200, as shown in FIGS. 3D and 3E.

The third anode 120 c can be formed from a transparent conductivematerial such as indium-tin-oxide ITO, indium-zinc-oxide IZO oraluminum-zinc-oxide AZO, unlike the first and second anodes 120 a and120 b on the first substrate 100.

After the red and green color filter layers R and G and the third anode120 c are formed on the second substrate 200, a second organic lightemission layer 205 and a second cathode 306 are sequentially formed onthe entire surface of the second substrate 200, as shown in FIGS. 3F and3G. The second cathode 306 can be formed from the same transparentconductive material as the first cathode 106.

Thereafter, a reflective plate 307 is formed on the second cathode 306corresponding to the blue sub-pixel region, thereby completing thefabrication of an upper substrate 310.

In order to form the reflective plate 307, a metal film including a heatemission layer 334, first and second buffer layers 322 and 321 and ametal layer, which are stacked on a base substrate 333, is attached tothe second cathode 306. Also, either laser light is irradiated on a partof the metal film corresponding to the region in which the reflectiveplate 307 will be formed, or a high voltage is applied to a part of theheat emission layer 334 corresponding to the blue sub-pixel region.

The heat emission layer 334 can be formed from a metal, such asmolybdenum Mo, with superior heat absorptivity. Also, the heat emissionlayer is patterned and disposed on the base substrate 333 correspondingto the blue sub-pixel region.

When either laser light is irradiated or the high voltage is applied,the heat emission layer 334 generates high-temperature heat and forces apart of the metal layer on the second buffer layer 321 to be attached tothe second cathode 306. In accordance therewith, the reflective plate307 is formed on the second cathode 306 corresponding to the bluesub-pixel region. Although it is shown in the drawing, a referencenumber “308” not cited in the above description indicates a sacrificiallayer. The sacrificial layer 308 corresponds to the residual metal layerwhich remains on the metal film after the formation of the reflectiveplate 307.

The reflective plate 307 reflects blue light, which is generated in thesecond organic light emission layer 205 and entered through the secondcathode 306, toward the rear surface of the second substrate 200.

When the fabrication of the upper substrate 310 including the red andgreen color filter layers R and G and the third switching element T3 inthe blue sub-pixel region is completed, as shown in FIG. 3G, the uppersubstrate 310 and the lower substrate 110 are combined with each otherby means of an adhesive layer 250. As such, a completed organicelectroluminescent display device is produced.

The organic electroluminescent display device according to a secondembodiment of the present disclosure allows not only the red and greencolor filter layers R and G to be formed in the red and green sub-pixelregions, respectively, but also the second organic light emission layer205 emitting blue light to be formed in the blue sub-pixel region. Inother words, a blue color filter layer is not formed in the bluesub-pixel region.

Also, the first and second organic light emission layers 105 and 205 canbe formed on the first and second substrates 100 and 200 through thecoating process or the deposition process and without using any shadowmask. As such, the organic electroluminescent display device of thesecond embodiment can prevent the previous problems which had beengenerated in that of the related art due to the use of the shadow mask.

In the red sub-pixel region, the mixture of red light and green lightgenerated in the first organic light emission layer 105 is re-mixed withblue light generated in the second organic light emission layer 205. Assuch, the re-mixed light can be applied to the red color filter layer R.Therefore, red light can be output from the red sub-pixel. Similarly tothis, green light can be output from the green sub-pixel. Meanwhile, inthe blue sub-pixel region, only blue light generated in the secondorganic light emission layer 205 can be output through the third anode120 c.

The organic electroluminescent display device and the fabricating methodthereof according to the present embodiment allow the organic lightemission layer to be not only distributed to the two substrates but alsoformed through only the coating process or the deposition processwithout using any shadow mask. As such, a large-sized screen and ahigh-definition image can be provided.

Moreover, the organic electroluminescent display device and thefabricating method thereof according to the present embodiment enablethe organic light emission layer to be formed without using any shadowmask. In accordance therewith, the deterioration of productivity ratiodue to the generation of different materials can be prevented.

FIGS. 4A through 4F are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to athird embodiment of the present disclosure.

In this disclosure, components of the third embodiment which aredistinguished from those of the first and second embodiments will bemainly described. Also, it will be easily understood to an ordinaryperson explanation regarding the other components of the thirdembodiment, which will be not explained in detail, upon theabove-mentioned descriptions of the first and second embodiments.

As shown in FIGS. 4A through 4F, a first switching element T1 and asecond switching element T2 are formed on the red and green sub-pixelregions of the first substrate 100, respectively. A passivation layer101 is formed on the entire surface of the first substrate 100 providedwith the first and second switching elements T1 and T2.

Subsequently, a first bank pattern 103, first and second anodes 120 aand 120 b and a reflective plate 407 are formed on the passivation layer101. The first and second anodes 120 a and 120 b are formed on regionsof the passivation layer 101 opposite to red and green sub-pixels,respectively. The reflective plate 407 is formed on another region ofthe passivation layer 101 opposite to a blue sub-pixel. The first andsecond anodes 120 a and 120 b and the reflective plate 407 can besimultaneously formed.

However, the first and second anodes 120 a and 120 b and the reflectiveplate 407 can be formed before the first bank pattern 103 used toseparate the sub-pixels from one another, after the passivation layer101 is formed on the first substrate 100 and a contact hole formationprocess is performed for the passivation layer 101.

Thereafter, as shown in FIGS. 4B and 4C, a first organic light emissionlayer 105 and a first cathode 106 are sequentially formed on the firstsubstrate 100 so that the fabrication of a lower substrate 410 for theorganic electroluminescent display device is completed. The firstcathode 106 can be formed from a transparent conductive material. Thefirst organic light emission layer 105 can be formed from an organicmaterial adapted to emit a mixture of red light and green light.

When the lower substrate 410 of the organic electroluminescent displaydevice is completely fabricated as described above, a third switchingelement T3, an insulation layer 201, a second bank pattern 203 defininga plurality of sub-pixel regions, red and green color filter layers Rand G, and a third anode 120 c are sequentially formed on a secondsubstrate 200, as shown in FIG. 4D.

The third anode 120 c is disposed in the blue sub-pixel region. Also,the third anode 120 c can be formed from a transparent conductivematerial such as indium-tin-oxide ITO, indium-zinc-oxide IZO oraluminum-zinc-oxide AZO, unlike the first and second anodes 120 a and120 b on the first substrate 100.

After the red and green color filter layers R and G and the third anode120 c are formed on the second substrate 200, a second organic lightemission layer 205 used to emit blue light and a second cathode 306 aresequentially formed on the entire surface of the second substrate 200,as shown in FIG. 4E. In accordance therewith, the fabrication of anupper substrate 510 is completed. The second cathode 306 can be formedfrom the same transparent conductive material as the first cathode 106.

When the fabrication of the upper substrate 510 including the red andgreen color filter layers R and G and the third switching element T3 inthe blue sub-pixel region is completed, as shown in FIG. 4F, the uppersubstrate 510 and the lower substrate 410 are combined with each otherby means of an adhesive layer 250. As such, a completed organicelectroluminescent display device is produced.

The organic electroluminescent display device according to a thirdembodiment of the present disclosure allows not only the red and greencolor filter layers R and G to be formed in the red and green sub-pixelregions, respectively, but also the second organic light emission layer205 emitting blue light to be formed in the blue sub-pixel region. Inother words, a blue color filter layer is not formed in the bluesub-pixel region.

Also, the first and second organic light emission layers 105 and 205 canbe formed on the first and second substrates 100 and 200 through thecoating process or the deposition process and without using any shadowmask. As such, the organic electroluminescent display device of thethird embodiment can prevent the previous problems which had beengenerated in that of the related art due to the use of the shadow mask.

FIGS. 5A through 5E are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to afourth embodiment of the present disclosure.

As shown in FIGS. 5A through 5E, a first switching element T1, a secondswitching element T2 and a third switching element T3 are formed on red,green and blue sub-pixel regions of a substrate 400, respectively. Apassivation layer 401 is formed on the entire surface of the substrate400 provided with the first through third switching elements T1 throughT3.

Although the structure of each switching element T1 through T3 is notshown in the drawings, one of a top-gate thin-film transistor and abottom-gate thin-film transistor, which are generally being used in theorganic electroluminescent display devices, can be formed as a switchingelement.

After the above-mentioned passivation layer 401 is formed on thesubstrate 400, a bank pattern 403 used to define sub-pixels is formed onthe passivation layer 401. The bank pattern 403 can be prepared byforming a metal film or an opaque resin layer on the entire surface ofthe substrate 400 and performing a masking process for the metal film orthe opaque resin layer. The metal film can be from a metal material suchas chromium Cr.

When the bank pattern 403 is formed on the substrate 400 as describedabove, a red color filter layer R and a green color filter layer G areformed in exposed regions of the passivation layer 401 corresponding tothe red and green sub-pixel regions, respectively. Subsequently, acontact hole formation process is performed for the red and green colorfilter layers R and G and the bank pattern 403, in order to expose drainelectrodes of the first through third switching elements T1 through T3.

Thereafter, first through third anodes 420 a through 420 c are formed inthe red, green and blue sub-pixel regions R, G and B of the substrate400. The first through third anodes 420 a through 420 c can be preparedby forming a metal film on the entire surface of the substrate 400provided with the bank pattern 403 and the red and green color filterlayers R and G and performing a masking process and an etch process forthe metal film. The metal film can be formed from a transparentconductive material such as indium-tin-oxide ITO, indium-zinc-oxide IZOor aluminum-zinc-oxide AZO.

Subsequently, a first organic light emission layer 405 is formed on theentire surface of the substrate 400 provided with the first throughthird anodes 420 a through 420 c using one of a coating process and adeposition process. Also, a metal layer 406 is formed on the firstorganic light emission layer 405. A laser irradiation process or an etchprocess is performed for a part of the metal layer 406 corresponding tothe blue sub-pixel region so that apart of the metal layer correspondingto the blue sub-pixel region is removed. In accordance therewith, afirst cathode 406 a is formed on the first organic light emission layer405 corresponding to the red and green sub-pixel regions. In otherwords, the first cathode 406 a exposes the first organic light emissionlayer corresponding to the blue sub-pixel region. The metal layer 406can be formed from one of magnesium Mg, calcium Ca, aluminum Al, silverAg, lithium Li and alloys thereof.

After the formation of the first cathode 406 a, the laser irradiationprocess is re-performed for the exposed portion of the first organiclight emission layer 405 corresponding to the blue sub-pixel region, inorder to remove the exposed portion of the first organic light emissionlayer 405. In accordance therewith, an organic light emission layerpattern 405 a is derived from the first organic light emission layer405. The first organic light emission layer 405 can be formed from anorganic material capable of emitting a mixture of red light and greenlight. The organic light emission layer pattern 405 a is formed only inthe red and green sub-pixel regions.

When the organic light emission layer pattern 405 a and the firstcathode 406 a are formed on the substrate 400 as described above, asurface cleaning process is performed for the substrate 400 providedwith the first cathode 406 a, as shown in FIG. 5D. Continuously, asecond organic light emission layer 415 is formed on the entire surfaceof the substrate 400 provided with the first cathode 406 a, as shown inFIG. 5E. The second organic light emission layer 415 can be formedthrough one of the coating process and the deposition process, like thefirst organic light emission layer 405. However, the second organiclight emission layer 415 is formed from another organic material capableof emitting blue light, unlike the first organic light emission layer405.

Afterward, a second cathode 417 is formed on the second organic lightemission layer 415 by depositing a metal layer on the entire surface ofthe substrate 400. The second cathode 417 can be formed from an opaquemetal with high reflectance.

The organic electroluminescent display device of the fourth embodimentis described as having a structure of emitting light toward the rearsurface of the substrate 400. However, the organic electroluminescentdisplay device of the fourth embodiment can emit light toward thecathodes. In this case, the first through third anodes 420 a through 420c are formed from one of magnesium Mg, calcium Ca, aluminum Al, silverAg, lithium Li and alloys thereof, and the first and second cathodes 406a and 417 are formed from a transparent conductive material such asindium-tin-oxide ITO, indium-zinc-oxide IZO or aluminum-zinc-oxide AZO.

In this way, the fourth embodiment allows the red and green color filterlayers R and G, the organic light emission layer pattern 405 a emittinga mixture of red light and green light, and the first cathode 406 a tobe sequentially formed only on the red and green sub-pixel regions.Meanwhile, the second organic light emission layer 415 emitting bluelight and the second cathode 417 are sequentially formed in the bluesub-pixel region without forming any color filter layer. As such, aprocess of forming a blue color filter layer can be omitted.

Also, the first and second organic light emission layers 405 and 417 canbe formed through the coating process or the deposition process withoutusing any shadow mask. As such, the organic electroluminescent displaydevice of the fourth embodiment can prevent the previous problems whichhad been generated in that of the related art due to the use of theshadow mask.

Moreover, the mixture of red light and green light generated in theorganic light emission layer pattern 405 a is applied to the red andgreen color filter layers R and G. As such, red light and green lightcan be output from the red and green sub-pixel, respectively. Meanwhile,the blue sub-pixel allows blue light generated in the second organiclight emission layer 415 to be output. Therefore, the organicelectroluminescent display device of the fourth embodiment can display acolor image.

FIGS. 6A through 6E are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to afifth embodiment of the present disclosure.

The description of the fifth embodiment will be focused on componentsdistinguished from those of the fourth embodiment. Also, it will beeasily understood to an ordinary person explanation regarding the othercomponents of the fifth embodiment, which will be not explained indetail, upon the above-mentioned description of the fourth embodiment.

Referring to FIGS. 6A through 6E, a substrate 400 is prepared. Althoughthey are not shown in the drawings, a plurality of gate lines and aplurality of data lines crossing each other are formed on the substrate400 in such a manner as to define a plurality of sub-pixel regions.

As shown in the drawings, first through third switching elements T1through T3, are formed on the red, green and blue sub-pixel regions ofthe substrate 400, respectively. Also, a passivation layer 401 and abank pattern 403 are sequentially formed on the substrate 400 providedwith the first through third switching elements T1 through T3.

When the bank pattern 403 is formed on the substrate 400 as describedabove, red and green color filter layers R and G are formed in exposedregions of the passivation layer 401 corresponding to the red and greensub-pixel regions, respectively. Also, first through third anodes 420 athrough 420 c are formed in the red, green and blue sub-pixel regions R,G and B of the first substrate 400 in such a manner as to be connectedto drain electrodes of the first through third switching elements T1through T3, respectively. Subsequently, a first organic light emissionlayer 405 is formed on the entire surface of the substrate 400 throughone of a coating process and a deposition process. Thereafter, a firstcathode 406 a is formed on the first organic light emission layer 405opposite to the red and green sub-pixels using an electrode film whichis configured with a base substrate 450, a transmission layer 452, anadhesive layer 453 and a metal layer.

The transmission layer 452 of the electrode film has a property of beingseparate from the metal layer when ultraviolet rays are irradiated.Also, the transmission layer 452 is formed on the base substrate 450opposite to the red and green sub-pixel regions. Meanwhile, the adhesivelayer 453 is formed in the same layer as the transmission layer 452 andon the base substrate 450 opposite to the blue sub-pixel region.

In order to form the first cathode 406 a, the ultraviolet rays areirradiated to the entire surface of the electrode film which brings intocontact with the first organic light emission layer 405. At this time, apart of the metal layer opposite to the transmission layer 452 isseparated from the electrode film and attached to the first organiclight emission layer 405, thereby forming the first cathode 406 a.Meanwhile, the metal layer opposite to the adhesive layer 453 cannot beseparated from the electrode film. In other words, the metal layeropposite to the adhesive layer 453 remains in the electrode film as asacrificial layer 456.

The first cathode 406 a can be formed from an opaque metal with highreflectance. For example, the first cathode 406 a can be formed from oneof magnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li andalloys thereof.

After the formation of the first cathode 406 a, the laser irradiationprocess is performed for the exposed portion of the first organic lightemission layer 405 corresponding to the blue sub-pixel region, in orderto remove the exposed portion of the first organic light emission layer405. In accordance therewith, an organic light emission layer pattern405 a is derived from the first organic light emission layer 405. Theorganic light emission layer 405 can be formed from an organic materialcapable of emitting a mixture of red light and green light. The organiclight emission layer pattern 405 a is formed only in the red and greensub-pixel regions.

When the organic light emission layer pattern 405 a and the firstcathode 406 a are formed on the substrate 400 as described above, asurface cleaning process is performed for the substrate 400 providedwith the first cathode 406 a, as shown in FIG. 6D. Subsequently, asecond organic light emission layer 415 is formed on the entire surfaceof the substrate 400 provided with the first cathode 406 a, as shown inFIG. 6E. The second organic light emission layer 415 can be formedthrough one of the coating process and the deposition process, like thefirst organic light emission layer 405. However, the second organiclight emission layer 415 is formed from another organic material capableof emitting blue light, unlike the first organic light emission layer405.

Afterward, a second cathode 417 is formed on the second organic lightemission layer 415 by depositing a metal layer on the entire surface ofthe substrate 400. The second cathode 417 can be formed from an opaquemetal with high reflectance.

In this way, the fifth embodiment allows the organic light emissionlayer pattern 405 a emitting a mixture of red light and green light andthe first cathode 406 a to be sequentially formed only on the red andgreen sub-pixel regions. Meanwhile, the second organic light emissionlayer 415 emitting blue light and the second cathode 417 aresequentially formed in the blue sub-pixel region.

The organic electroluminescent display device of the fifth embodiment isdescribed as having a structure of emitting light toward the rearsurface of the substrate 400. However, the organic electroluminescentdisplay device of the fifth embodiment can emit light toward thecathodes. In this case, the first through third anodes 420 a through 420c are formed from one of magnesium Mg, calcium Ca, aluminum Al, silverAg, lithium Li and alloys thereof, and the first and second cathodes 406a and 417 are formed from a transparent conductive material such asindium-tin-oxide ITO, indium-zinc-oxide IZO or aluminum-zinc-oxide AZO.

Particularly, the first and second organic light emission layers 405 and417 can be formed on the substrate without using any shadow mask. Assuch, the organic electroluminescent display device of the fifthembodiment can prevent the previous problems which had been generated inthat of the related art due to the use of the shadow mask.

Moreover, the mixture of red light and green light generated in theorganic light emission layer pattern 405 a is applied to the red andgreen color filter layers R and G. As such, red light and green lightcan be output from the red and green sub-pixel, respectively. Meanwhile,the blue sub-pixel allows blue light generated in the second organiclight emission layer 415 to be output. Therefore, the organicelectroluminescent display device of the fifth embodiment can display acolor image.

FIGS. 7A through 7E are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to asixth embodiment of the present disclosure.

The description of the sixth embodiment will be focused on componentsdistinguished from those of the fourth embodiment. Also, it will beeasily understood to an ordinary person explanation regarding the othercomponents of the sixth embodiment, which will be not explained indetail, upon the above-mentioned descriptions of the fourth and fifthembodiments.

As shown in FIGS. 7A through 7E, first through third switching elementsT1 through T3, a passivation layer 401, a bank pattern 403, red andgreen color filter layers R and G, and first through third anodes 420 athrough 420 c are sequentially formed on a substrate 400.

In the sixth embodiment of the present disclosure, a photo resistpattern 470 is formed on the third anode 420 c of the blue sub-pixel.The photo resist pattern 470 can be prepared by forming a photo resistfilm on the entire surface of the above-mentioned substrate 400 andperforming exposure and development processes for the photo resist film.

Subsequently, a first organic light emission layer 405 is formed on theentire surface of the substrate 400 provided with the photo resistpattern 470, as shown in FIG. 7B. Also, a metal layer 406 is formed onthe first organic light emission layer 405.

Thereafter, the photo resist pattern 470 is removed through a lift-offprocess which uses stripper solution. At the same time, the firstorganic light emission layer 405 and the metal layer 406, which areformed on the photo resist pattern 470, are also removed. In accordancetherewith, an organic light emission layer pattern 405 a and a firstcathode 406 a are derived from the first organic light emission layer405 and the metal layer 406, respectively, as shown in FIG. 7C.

The first cathode 406 a can be formed from an opaque metal with highreflectance. For example, the first cathode 406 a can be formed from oneof magnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li andalloys thereof.

When the first cathode 406 a is formed on the substrate 400 as describedabove, a surface cleaning process is performed for the substrate 400provided with the first cathode 406 a, as shown in FIG. 5D.Continuously, a second organic light emission layer 415 is formed on theentire surface of the substrate 400 provided with the first cathode 406a, as shown in FIG. 5E. The second organic light emission layer 415 canbe formed through one of the coating process and the deposition process,like the first organic light emission layer 405. However, the secondorganic light emission layer 415 is formed from another organic materialcapable of emitting blue light, unlike the first organic light emissionlayer 405.

Afterward, a second cathode 417 is formed on the second organic lightemission layer 415 by depositing a metal layer on the entire surface ofthe substrate 400. The second cathode 417 can be formed from an opaquemetal with high reflectance.

The organic electroluminescent display device of the sixth embodiment isdescribed as having a structure of emitting light toward the rearsurface of the substrate 400. However, the organic electroluminescentdisplay device of the fourth embodiment can emit light toward thecathodes. In this case, the first through third anodes 420 a through 420c are formed from one of magnesium Mg, calcium Ca, aluminum Al, silverAg, lithium Li and alloys thereof, and the first and second cathodes 406a and 417 are formed from a transparent conductive material such asindium-tin-oxide ITO, indium-zinc-oxide IZO or aluminum-zinc-oxide AZO.

Such a sixth embodiment allows the organic light emission layer pattern405 a emitting a mixture of red light and green light and the firstcathode 406 a to be sequentially formed in the red and green sub-pixelregions. Also, the sixth embodiment enables the second organic lightemission layer 415 emitting blue light and the second cathode 417 to besequentially formed in the blue sub-pixel region.

Also, the first and second organic light emission layers 405 and 417 canbe formed through the coating process or the deposition process withoutusing any shadow mask. As such, the organic electroluminescent displaydevice of the sixth embodiment can prevent the previous problems whichhad been generated in that of the related art due to the use of theshadow mask.

Moreover, the mixture of red light and green light generated in theorganic light emission layer pattern 405 a is applied to the red andgreen color filter layers R and G. As such, red light and green lightcan be output from the red and green sub-pixel, respectively. Meanwhile,the blue sub-pixel allows blue light generated in the second organiclight emission layer 415 to be output. Therefore, the organicelectroluminescent display device of the sixth embodiment can display acolor image.

FIG. 8 is a cross-sectional view illustrating a method of fabricating anorganic electroluminescent display device according to a seventhembodiment of the present disclosure.

The seventh embodiment corresponds to a modification of the fourthembodiment. As such, the description of the seventh embodiment will befocused on components distinguished from those of the fourth embodiment.Also, it will be easily understood to an ordinary person explanationregarding the other components of the seventh embodiment, which will benot explained in detail, upon the above-mentioned description of thefourth embodiment.

Referring to FIG. 8, the seventh embodiment allows the processes of thefourth embodiment, which are shown in FIGS. 5A through 5C and includethe formation processes of the organic light emission layer pattern 405a and the first cathode 406 a, to be sequentially performed for asubstrate 400. Subsequently, a surface cleaning process is performed forthe substrate 400 provided with the organic light emission layer pattern405 a and the first cathode 406 a.

Thereafter, a second organic light emission layer 490 is formed on thethird anode 420 c within the blue sub-pixel region using one of anorganic vapor jet printing method, a nozzle-jet printing method and anink-jet printing method.

The second organic light emission layer 490 on the third anode 420 cwithin the blue sub-pixel region can be formed from an organic materialcapable of emitting blue light and in the same layer as the organiclight emission layer pattern 405 a. The second organic light emissionlayer 490 is formed to have the same height as the organic lightemission layer pattern 405 a.

When the second organic light emission layer 490 is formed on thesubstrate 400 as described above, a second cathode 480 is formed on thefirst cathode 106 a and the second organic light emission layer 490 bydepositing a metal material on the entire surface of the substrate 400.The second cathode 480 can be formed from an opaque metal with highreflectance. Also, the second cathode 480 comes into direct contact withthe first cathode 406 a.

The organic electroluminescent display device of the seventh embodimentis described as having a structure of emitting light toward the rearsurface of the substrate 400. However, the organic electroluminescentdisplay device of the seventh embodiment can emit light toward thecathodes. In this case, the first through third anodes 420 a through 420c are formed from one of magnesium Mg, calcium Ca, aluminum Al, silverAg, lithium Li and alloys thereof, and the first and second cathodes 406a and 480 are formed from a transparent conductive material such asindium-tin-oxide ITO, indium-zinc-oxide IZO or aluminum-zinc-oxide AZO.

In the organic electroluminescent display device of the seventhembodiment, the second organic light emission layer 490 is formed in thesame layer as the organic light emission layer pattern 405 a.

Also, both the first and second organic light emission layers 405 and490 can be formed without using any shadow mask. As such, the organicelectroluminescent display device of the seventh embodiment can preventthe previous problems which had been generated in that of the relatedart due to the use of the shadow mask.

Moreover, the mixture of red light and green light generated in theorganic light emission layer pattern 405 a is applied to the red andgreen color filter layers R and G. As such, red light and green lightcan be output from the red and green sub-pixel, respectively. Meanwhile,the blue sub-pixel allows blue light generated in the second organiclight emission layer 415 to be output. Therefore, the organicelectroluminescent display device of the seventh embodiment can displaya color image.

FIGS. 9A through 9F are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to aneighth embodiment of the present disclosure.

Referring to FIGS. 9A through 9F, a substrate 500 is prepared. Althoughthey are not shown in the drawings, a plurality of gate lines and aplurality of data lines crossing each other are formed on the substrate500 in such a manner as to define a plurality of sub-pixel regions.

The sub-pixel regions are classified into red, green and blue sub-pixelregions. Also, thin film transistors TFT being used as switchingelements are formed in the red and green sub-pixel regions.

As shown in the drawings, first through third switching elements T1through T3 are formed in the red, green and blue sub-pixel regions ofthe substrate 500, respectively. A passivation layer 501 is formed onthe entire surface of the substrate 500 provided with the first throughthird switching elements T1 through T3.

Although the structure of each switching element T1 and T2 is not shownin the drawings, one of a top-gate thin-film transistor and abottom-gate thin-film transistor, which are generally being used in theorganic electroluminescent display devices, can be formed as a switchingelement.

After the above-mentioned passivation layer 501 is formed on thesubstrate 500, a bank pattern 503 used to define sub-pixels is formed onthe passivation layer 501. The bank pattern 503 can be prepared byforming a metal film or an opaque resin layer on the entire surface ofthe substrate 500 and performing a masking process for the metal film orthe opaque resin layer. The metal film can be from a metal material suchas chromium Cr.

When the bank pattern 503 is formed on the substrate 500 as describedabove, a red color filter layer R and a green color filter layer G areformed in exposed regions of the passivation layer 501 corresponding tothe red and green sub-pixel regions, respectively. Subsequently, acontact hole formation process is performed for the red and green colorfilter layers R and G and the bank pattern 503, in order to expose drainelectrodes of the first through third switching elements T1 through T3.

Thereafter, first through third anodes 520 a through 520 c are formed inthe red, green and blue sub-pixel regions R, G and B of the substrate500. The first through third anodes 520 a through 520 c can be preparedby forming a metal film on the entire surface of the substrate 500provided with the bank pattern 503 and the red and green color filterlayers R and G and performing a masking process and an etch process forthe metal film. The metal film can be formed from a transparentconductive material such as indium-tin-oxide ITO, indium-zinc-oxide IZOor aluminum-zinc-oxide AZO.

Subsequently, a hole support layer 504 is formed on the entire surfaceof the substrate 500 provided with the first through third anodes 520 athrough 520 c using one of a coating procedure and a deposition process.Also, a first organic light emission layer 505 is formed on the holesupport layer 504 corresponding to the red and green sub-pixel regionsusing a mask 650. The hole support layer 504 can include a holeinjection layer HIL and a hole transport layer HTL. The first organiclight emission layer 505 can be formed from an organic material capableof emitting a mixture of red light and green light.

Afterward, a second organic light emission layer 506 is formed on theentire surface of the substrate 500 provided with the first organiclight emission layer 505, as shown in FIG. 9D. The second organic lightemission layer 506 can be formed through one of the coating process andthe deposition process. Also, the second organic light emission layer506 is formed from another organic material capable of emitting bluelight, unlike the first organic light emission layer 505. Moreover, thesecond organic light emission layer 506 is formed to cover the entiresurface of the substrate 500.

When the first and second organic light emission layers 505 and 506 areformed on the substrate 500 as described above, an electron supportlayer 507 is formed on the second organic light emission layer 506, asshown in FIG. 9E. The electron support layer 507 can include an electroninjection layer EIL and an electron transport layer ETL.

After the electron support layer 507 is formed on the substrate 500 asdescribed above, a cathode 509 is formed on the electron support layer507 by depositing a metal layer on the entire surface of the substrate500, as shown in FIG. 9F. The cathode 509 can be formed from one ofmagnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li and alloysthereof.

The organic electroluminescent display device of the eighth embodimentis described as having a structure of emitting light toward the rearsurface of the substrate 500. However, the organic electroluminescentdisplay device of the eighth embodiment can have another structureadapted to emit light toward the cathode. In this case, the firstthrough third anodes 520 a through 520 c are formed from one ofmagnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li and alloysthereof, and the cathode 509 is formed from a transparent conductivematerial such as indium-tin-oxide ITO, indium-zinc-oxide IZO oraluminum-zinc-oxide AZO.

In this way, the eighth embodiment allows the red and green color filterlayers R and G and the first organic light emission layer 505 emitting amixture of red light and green light to be sequentially formed only onthe red and green sub-pixel regions. Meanwhile, the second organic lightemission layer 506 emitting blue light is formed in the blue sub-pixelregion without forming any color filter layer and without using anyshadow mask. Therefore, the organic electroluminescent display device ofthe eighth embodiment can prevent the previous problems which had beengenerated in that of the related art due to the use of the shadow mask.

Moreover, in the red sub-pixel region, the mixture of red light andgreen light generated in the first organic light emission layer 505 isre-mixed with blue light generated in the second organic light emissionlayer 506. As such, the re-mixed light can pass through the red colorfilter layer R. Therefore, red light can be output from the redsub-pixel. Similarly to this, green light can be output from the greensub-pixel. Meanwhile, in the blue sub-pixel region, only blue lightgenerated in the second organic light emission layer 506 can be outputthrough the third anode 520 c. As a result, the organicelectroluminescent display device of the eighth embodiment can enablered, green and blue lights to be output from the red, green and bluesub-pixel, thereby displaying a color image.

FIGS. 10A through 10F are cross-sectional views illustrating a method offabricating an organic electroluminescent display device according to aninth embodiment of the present disclosure.

The description of the ninth embodiment will be focused on components ofthe ninth embodiment which are distinguished from those of the eighthembodiment will be mainly described. Also, it will be easily understoodto an ordinary person explanation regarding the other components of theninth embodiment, which will be not explained in detail, upon theabove-mentioned description of the eighth embodiment.

Referring to FIGS. 10A through 10F, first through third switchingelements T1 through T3, a passivation layer 501, a bank pattern 503, redand green color filter layers R and G, first through third anodes 520 athrough 520 c within red, green and blue sub-pixel regions, and a holesupport layer 504 are sequentially formed on a substrate 500, like thosein the eight embodiment.

Subsequently, a first organic light emission layer 605 is formed on thehole support layer 504 using one of an ink-jet printing method and anozzle-jet printing method. The first organic light emission layer 605is formed on the hole support layer 504 corresponding to the red andgreen sub-pixel regions. The hole support layer 504 can include a holeinjection layer HIL and a hole transport layer HTL. A reference number“750” in FIG. 10C indicates a dispenser which can be used as one of anozzle and an ink-jet. The first organic light emission layer 505 can beformed from an organic material capable of emitting a mixture of redlight and green light.

Afterward, a second organic light emission layer 606 is formed on theentire surface of the substrate 500 provided with the first organiclight emission layer 605, as shown in FIG. 10D. The second organic lightemission layer 606 can be formed through one of the coating process andthe deposition process. Also, the second organic light emission layer606 is formed from another organic material capable of emitting bluelight, unlike the first organic light emission layer 605. Moreover, thesecond organic light emission layer 606 is formed to cover the entiresurface of the substrate 500.

When the first and second organic light emission layers 605 and 606 areformed on the substrate 500 as described above, an electron supportlayer 607 is formed on the second organic light emission layer 606, asshown in FIG. 10E. The electron support layer 607 can include anelectron injection layer EIL and an electron transport layer ETL.

After the electron support layer 607 is formed on the substrate 500 asdescribed above, a cathode 609 is formed on the electron support layer607 by depositing a metal layer on the entire surface of the substrate500, as shown in FIG. 10F. The cathode 609 can be formed from one ofmagnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li and alloysthereof.

The organic electroluminescent display device of the ninth embodiment isdescribed as having a structure of emitting light toward the rearsurface of the substrate 500. However, the organic electroluminescentdisplay device of the ninth embodiment can have another structureadapted to emit light toward the cathode. In this case, the firstthrough third anodes 520 a through 520 c are formed from one ofmagnesium Mg, calcium Ca, aluminum Al, silver Ag, lithium Li and alloysthereof, and the cathode 609 is formed from a transparent conductivematerial such as indium-tin-oxide ITO, indium-zinc-oxide IZO oraluminum-zinc-oxide AZO.

In this way, the ninth embodiment allows the red and green color filterlayers R and G and the first organic light emission layer 605 emitting amixture of red light and green light to be sequentially formed only inthe red and green sub-pixel regions. Meanwhile, the second organic lightemission layer 606 emitting blue light is formed in the blue sub-pixelregion without forming any color filter layer and without using anyshadow mask. Therefore, the organic electroluminescent display device ofthe ninth embodiment can prevent the previous problems which had beengenerated in that of the related art due to the use of the shadow mask.

Moreover, in the red sub-pixel region, the mixture of red light andgreen light generated in the first organic light emission layer 605 isre-mixed with blue light generated in the second organic light emissionlayer 606. As such, the re-mixed light can pass through the red colorfilter layer R. Therefore, red light can be output from the redsub-pixel. Similarly to this, green light can be output from the greensub-pixel. Meanwhile, in the blue sub-pixel region, only blue lightgenerated in the second organic light emission layer 606 can be outputthrough the third anode 520 c. As a result, the organicelectroluminescent display device of the eighth embodiment can enablered, green and blue lights to be output from the red, green and bluesub-pixel, thereby displaying a color image.

Although the present disclosure has been limitedly explained regardingonly the embodiments described above, it should be understood by theordinary skilled person in the art that the present disclosure is notlimited to these embodiments, but rather that various changes ormodifications thereof are possible without departing from the spirit ofthe present disclosure. Accordingly, the scope of the present disclosureshall be determined only by the appended claims and their equivalents.

What is claimed is:
 1. An organic electroluminescent display device,comprising: first through third switching elements formed in red, greenand blue sub-pixel regions into which a substrate is defined,respectively; a passivation layer entirely formed on the substrate whichis provided with the first through third switching elements; red andgreen color filter layers formed on the passivation layer correspondingto the red and green sub-pixel regions; first through third anodesformed in the red, green and blue sub-pixel regions, respectively; ahole support layer formed on the substrate which is provided with thefirst through third anodes; a first organic light emission layer formedon the hole support layer corresponding to the red and green sub-pixelregions; a second organic light emission layer formed on the substratewhich is provided with the first organic light emission layer; anelectron support layer formed on the second organic light emissionlayer; and a cathode formed on the electron support layer.
 2. Theorganic electroluminescent display device of claim 1, wherein the firstand second anodes are formed on the red and green color filter layers,respectively.
 3. The organic electroluminescent display device of claim1, wherein the third anode is formed on the passivation layercorresponding to the blue sub-pixel region.
 4. The organicelectroluminescent display device of claim 1, wherein the first throughthird anodes are formed from a transparent conductive material such asone of indium-tin-oxide ITO, indium-zinc-oxide IZO andaluminum-zinc-oxide AZO.
 5. The organic electroluminescent displaydevice of claim 1, wherein the cathode is formed from one of magnesiumMg, calcium Ca, aluminum Al, silver Ag, lithium Li and alloys thereof.6. The organic electroluminescent display device of claim 1, wherein thefirst organic light emission layer is formed from an organic materialadapted to generate a mixture of red light and green light.
 7. Theorganic electroluminescent display device of claim 1, wherein the secondorganic light emission layer is formed from an organic material adaptedto generate blue light.